1. Field of the Invention
The present invention relates to electronic display, and more particularly, to projection display and flat panel display based on a novel phenomenon of voltage-induced color-selective absorption with surface plasmons.
2. Prior Art
The high-definition television (HDTV) is one of the most challenging technologies. HDTV projectors are the most favorable devices among HDTV devices because of their big screen size. The current color display projectors, either cathode ray tube projectors or liquid crystal light valve projectors, have very low efficiencies. Their brightness is limited, their structures are complex, and their power consumptions are high.
It is well known that, for prism coupling, surface plasmon resonance waves can be generated at a metal/dielectric interface by a p-polarized light. At surface plasmon resonance, the reflected light vanishes--attenuated total reflection (ATR). This resonance depends on the dielectric constants of both the metal and the dielectric. If an electro-optic material is used as the dielectric, when voltage is applied on the electro-optic material, the dielectric constant of the electro-optic material will change, and the intensity of reflected light can be modulated. There are many reports of using surface plasmon waves to build a light intensity modulator. See, for example, "Electrooptic reflection with surface plasmons" by Yu Wang and H. J. Simon, Optical and Quantum Electronics, vol. 25, pages S925-S933; "Surface-plasmon spatial light modulators based on liquid crystal" by M. E. Caldwell and E. M. Yeatman, Applied Optics, Vol. 31, pages 3880-3891; "All-optical spatial light modulator with surface plasmon resonance" by T. Okamoto, et al., Optics Letters, Vol. 18, pages 1570-1572; U.S. Pat. No. 4,247,796; U.S. Pat. No. 4,451,123; U.S. Pat. No. 5,155,617; U.S. Pat. No. 5,157,541; U.S. Pat. No. 5,347,395; U.S. Pat. No. 5,351,127. All of these devices used lasers as the light sources.
Recently, a new phenomenon of voltage-induced color-selective absorption with surface plasmons has been discovered; "Voltage-induced color-selective absorption with surface plasmons" by Yu Wang, to be published. This phenomenon shows that, when surface plasmon waves are excited at a metal/liquid crystal interface, not only the intensity of reflected light, but also the spectrum of the reflected light can be controlled by an external voltage. The surface plasmon resonance band strongly depends on the materials used for the metal film, by choosing different metal materials, the resonance spectrum band can have a range from less than 50 nm to cover all of the optical visible wavelengths.
Here I introduce my invention of surface plasmon high efficiency HDTV projector, which is based on the voltage-induced color-selective absorption with surface plasmons, is able to generate high brightness image on a big screen with high optical efficiency. This invention does not need color filters to create the color, this invention has fast switching time, this invention can be easily addressed by using semiconductor chips as the substrates, this invention is relatively easy to be fabricated, and this invention can be more efficiently cooled since it is working at the reflection mode.